TS-PC short defects are some of the most common and detrimental failure mechanisms for advanced process technology development in MOSFET device manufacturing. In-line detection of TS-PC short defects is especially challenging for new shorting mechanisms that can occur on an atomic scale due to new material/process flow implementation. Generally, critical TS-PC short defects cannot be detected by optical inspection methodology due to both resolution and contrast limitations.
Electron beam inspection (EBI) has been the most popular in-line detection method for detecting TS-PC electric defects at the gate contact (CB) chemical mechanical polishing (CMP) (CB-CMP) stage of device processing. Currently, CB-CMP is the only check point for TS-PC short defects. However, the cycle time is too long and, therefore, a defect may already be present at the TS-CMP stage. Detection of TS-PC short defects at the TS-CMP stage is currently not possible due to fundamental challenges. Early detection of TS-PC short defects at the TS-CMP stage is of great practical value in terms of cycle time, early warning of process excursion, and reducing costs for high volume manufacturing.
A need therefore exists for methodology enabling in-line detection of TS-PC defects at the TS-CMP processing stage.